1 files changed, 189 insertions, 0 deletions
diff --git a/apps/web/src/app/api/transcribe/route.ts b/apps/web/src/app/api/transcribe/route.ts
new file mode 100644
index 00000000..9a497f65
--- /dev/null
+++ b/apps/web/src/app/api/transcribe/route.ts
@@ -0,0 +1,189 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { env } from "@/env";
+import { baseRateLimit } from "@/lib/rate-limit";
+import { isTranscriptionConfigured } from "@/lib/transcription-utils";
+
+const transcribeRequestSchema = z.object({
+  filename: z.string().min(1, "Filename is required"),
+  language: z.string().optional().default("auto"),
+  decryptionKey: z.string().min(1, "Decryption key is required").optional(),
+  iv: z.string().min(1, "IV is required").optional(),
+});
+
+const modalResponseSchema = z.object({
+  text: z.string(),
+  segments: z.array(
+    z.object({
+      id: z.number(),
+      seek: z.number(),
+      start: z.number(),
+      end: z.number(),
+      text: z.string(),
+      tokens: z.array(z.number()),
+      temperature: z.number(),
+      avg_logprob: z.number(),
+      compression_ratio: z.number(),
+      no_speech_prob: z.number(),
+    })
+  ),
+  language: z.string(),
+});
+
+const apiResponseSchema = z.object({
+  text: z.string(),
+  segments: z.array(
+    z.object({
+      id: z.number(),
+      seek: z.number(),
+      start: z.number(),
+      end: z.number(),
+      text: z.string(),
+      tokens: z.array(z.number()),
+      temperature: z.number(),
+      avg_logprob: z.number(),
+      compression_ratio: z.number(),
+      no_speech_prob: z.number(),
+    })
+  ),
+  language: z.string(),
+});
+
+export async function POST(request: NextRequest) {
+  try {
+    // Rate limiting
+    const ip = request.headers.get("x-forwarded-for") ?? "anonymous";
+    const { success } = await baseRateLimit.limit(ip);
+    const origin = request.headers.get("origin");
+
+    if (!success) {
+      return NextResponse.json({ error: "Too many requests" }, { status: 429 });
+    }
+
+    // Check transcription configuration
+    const transcriptionCheck = isTranscriptionConfigured();
+    if (!transcriptionCheck.configured) {
+      console.error(
+        "Missing environment variables:",
+        JSON.stringify(transcriptionCheck.missingVars)
+      );
+
+      return NextResponse.json(
+        {
+          error: "Transcription not configured",
+          message: `Auto-captions require environment variables: ${transcriptionCheck.missingVars.join(", ")}. Check README for setup instructions.`,
+        },
+        { status: 503 }
+      );
+    }
+
+    // Parse and validate request body
+    const rawBody = await request.json().catch(() => null);
+    if (!rawBody) {
+      return NextResponse.json(
+        { error: "Invalid JSON in request body" },
+        { status: 400 }
+      );
+    }
+
+    const validationResult = transcribeRequestSchema.safeParse(rawBody);
+    if (!validationResult.success) {
+      return NextResponse.json(
+        {
+          error: "Invalid request parameters",
+          details: validationResult.error.flatten().fieldErrors,
+        },
+        { status: 400 }
+      );
+    }
+
+    const { filename, language, decryptionKey, iv } = validationResult.data;
+
+    // Prepare request body for Modal
+    const modalRequestBody: any = {
+      filename,
+      language,
+    };
+
+    // Add encryption parameters if provided (zero-knowledge)
+    if (decryptionKey && iv) {
+      modalRequestBody.decryptionKey = decryptionKey;
+      modalRequestBody.iv = iv;
+    }
+
+    // Call Modal transcription service
+    const response = await fetch(env.MODAL_TRANSCRIPTION_URL, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify(modalRequestBody),
+    });
+
+    if (!response.ok) {
+      const errorText = await response.text();
+      console.error("Modal API error:", response.status, errorText);
+
+      let errorMessage = "Transcription service unavailable";
+      try {
+        const errorData = JSON.parse(errorText);
+        errorMessage = errorData.error || errorMessage;
+      } catch {
+        // Use default message if parsing fails
+      }
+
+      return NextResponse.json(
+        {
+          error: errorMessage,
+          message: "Failed to process transcription request",
+        },
+        { status: response.status >= 500 ? 502 : response.status }
+      );
+    }
+
+    const rawResult = await response.json();
+    console.log("Raw Modal response:", JSON.stringify(rawResult, null, 2));
+
+    // Validate Modal response
+    const modalValidation = modalResponseSchema.safeParse(rawResult);
+    if (!modalValidation.success) {
+      console.error("Invalid Modal API response:", modalValidation.error);
+      return NextResponse.json(
+        { error: "Invalid response from transcription service" },
+        { status: 502 }
+      );
+    }
+
+    const result = modalValidation.data;
+
+    // Prepare and validate API response
+    const responseData = {
+      text: result.text,
+      segments: result.segments,
+      language: result.language,
+    };
+
+    const responseValidation = apiResponseSchema.safeParse(responseData);
+    if (!responseValidation.success) {
+      console.error(
+        "Invalid API response structure:",
+        responseValidation.error
+      );
+      return NextResponse.json(
+        { error: "Internal response formatting error" },
+        { status: 500 }
+      );
+    }
+
+    return NextResponse.json(responseValidation.data);
+  } catch (error) {
+    console.error("Transcription API error:", error);
+    return NextResponse.json(
+      {
+        error: "Internal server error",
+        message: "An unexpected error occurred during transcription",
+      },
+      { status: 500 }
+    );
+  }
+}